The field of electrosurgery includes a number of loosely related surgical techniques which have in common the application of electrical energy to modify the structure or integrity of patient tissue. Electrosurgical procedures usually operate through the application of very high frequency currents to cut or ablate tissue structures, where the operation can be monopolar or bipolar. Monopolar techniques rely on a separate electrode for the return of current that is placed away from the surgical site on the body of the patient, and where the surgical device defines only a single electrode pole that provides the surgical effect. Bipolar devices comprise two or more electrodes on the same support for the application of current between their surfaces.
Electrosurgical procedures and techniques are particularly advantageous because they generally reduce patient bleeding and trauma associated with cutting operations. Additionally, electrosurgical ablation procedures, where tissue surfaces and volume may be reshaped, cannot be duplicated through other treatment modalities.
Radiofrequency (RF) energy is used in a wide range of surgical procedures because it provides efficient tissue resection and coagulation and relatively easy access to the target tissues through a portal or cannula. Conventional monopolar high frequency electrosurgical devices typically operate by creating a voltage difference between the active electrode and the target tissue, causing an electrical arc to form across the physical gap between the electrode and tissue. At the point of contact of the electric arcs with tissue, rapid tissue heating occurs due to high current density between the electrode and tissue. This high current density causes cellular fluids to rapidly vaporize into steam, thereby producing a “cutting effect” along the pathway of localized tissue heating. Thus, the tissue is parted along the pathway of evaporated cellular fluid, inducing undesirable collateral tissue damage in regions surrounding the target tissue site. This collateral tissue damage often causes indiscriminate destruction of tissue, resulting in the loss of the proper function of the tissue. In addition, the device does not remove any tissue directly, but rather depends on destroying a zone of tissue and allowing the body to eventually remove the destroyed tissue.
Present electrosurgical devices used for cutting and dissection, such as monopolar electrocautery instruments, are able to cut and coagulate tissue, but cause high levels of collateral thermal damage to surrounding tissue. This limits the use of the monopoloar electrocautery devices to relatively “safe” areas away from sensitive structures such as blood vessels and nerves. In comparison, a traditional bipolar forceps may be used routinely for coagulation of small to medium sized vessels and may be preferred over monopolar electrocautery devices in the vicinity of sensitive structures because use of traditional bipolar forceps typically results in much less collateral thermal damage due to the localization of energy around the active and return electrodes at the tip of the device. However, these bipolar forceps do not have the ability to effectively cut or dissect tissue, requiring a physician needing to cut coagulated tissue to select another instrument (scissors, monopolar electrocautery, etc.) to complete the dissection. The necessity of so many instruments for one surgical procedure requires frequent switching between instruments, adding significant time to the procedure and frustration for the physician. Additionally, vessel sealing solutions presently exist for use where coagulation is desired and can typically involve use of sutures, clips, or energy-based devices to heat, seal, and/or cut large blood vessels. However, these devices are limited in that they do not provide fine dissection of tissue.
Accordingly, improved systems and methods in the configuration of surgical forceps are still desired with the ability to perform fine dissection of tissue, while preserving the ability to coagulate vessels and tissue. In particular, improved systems designed to integrate plasma-based cutting combined with effective coagulation abilities into a pair of bipolar forceps would provide a competitive advantage.